1. Technical Field
The present invention relates to a piezoelectric vibration module.
2. Description of the Related Art
Generally, in a portable electronic device such as a portable phone, an e-book terminal, a game machine, a portable multimedia player (PMP), or the like, a vibration function has been utilized for various uses.
Particularly, a vibration generating apparatus for generating the vibration has been mainly mounted in the portable electronic device to thereby be used as an alert function that is a soundless receiving signal.
In accordance with multi-functionalization of the portable electronic device, miniaturization, integration, and multi-functionalization of the vibration generating apparatus have been currently demanded.
Further, in accordance with the recent demand of users for simple usage of the portable electronic device, a touch type device performing an input by touching the electronic device has been generally adopted.
A concept of a currently generally used haptic device widely includes a concept of reflecting intuitive experience of an interface user and diversifying feedback for a touch, in addition to a concept of performing an input through a touch.
The above-mentioned haptic device generally provides vibration by repeating compression and/or expansion deformation by external power applied to a piezoelectric element, where a vibration generator using the piezoelectric element has been disclosed in Patent Document 1.
The vibration generator disclosed in Patent Document 1, which generates the vibration using mechanical energy, includes an upper case, a lower case, a piezoelectric element arranged on an upper side of the lower case and vibrating when a voltage is applied thereto, an elastic unit formed on an upper side of the piezoelectric element, and a weight body (or a weight) elastically supported by the elastic unit.
The piezoelectric element is applied with a current from the outside through a printed circuit board and responses to the current passing through the piezoelectric element to thereby generate physical moment or displacement force, such that translation is generated in a vertical or horizontal direction.
However, the vibration generator disclosed in Patent Document 1 does not describe in detail for the piezoelectric element and a current application scheme. As is well-known to those skilled in the art, when the piezoelectric element receives an application signal from the printed circuit board, a phenomenon in which an external electrode of the piezoelectric element soldered to an end portion of the printed circuit board is delaminated from the piezoelectric element by a repetitive vibration motion is often generated.
As such, another method capable of improving adhesion between the piezoelectric element and the external electrode under a continuous vibration state should be considered.